All good answers above, but I think that the core problem has not been properly diagnosed. If your rack is resonating then you need to reduce the amount of energy the rack (and your turntable) are exposed to. I'm guessing is that your rack is in between your speakers? Try moving the rack forward (away from the wall) and/or relocate the rack to one side of one speaker by at least 2'-3'. And you may try putting something absorbent on top of the shelf where the turntable sits, under the feet. Reflective surfaces can bounce low frequency energy to the TT and tonearm.
Audio Furniture has its own sound!
I've been using a stand that I made about 12 years ago. It's a flexi-type, with large rods, and I cut chrome curtain rods to cover the threaded rods. For shelves, I glued two pieces of MDF together, routed the edges, and painted with stone paint. Looks great, and it's really heavy and sturdy. But, I got a little tired of the look. I do think there is sound to furniture if it vibrates, but solid is solid, right?
So, I found a used Salamander Chameleon Sonoma 326. It matches the other furniture perfectly, looks great in the room, and has a perfect amount of storage. And, room on top for the turntable, as well as the Primaluna HP. Makes it look like simple and elegant system. The Salamander is very heavy, and made from solid wood.
But, when I hooked it up, that damn Salamander rings like a bell, and that energy totally transfers to the tonearm. I could not believe how horrible the system now sounded! Clearly the furniture was the problem. It was immediate, and completely ruined the sound. I think part of the issue is that it has a metal frame beneath the wood, and the sides seem to cause the metal frame to vibrate and ring.
Now, I'm on an adventure to see if I can fix it. My plan is 2 inch thick maple platform with vibrapods under the platform. A platform for the amp, a separate one for the TT, and vibrapods under the phono preamp. I have used an old tabletop from Ikea (it's honeycomb inside, and good dampener) with rubber feet, and it's helped a lot. But, I can still tell this vibrates slightly. I don't think it transfers much to the tonearm, but I'm still getting the maple platform.
I'm posting this because I've done some research oil Salamander as a TT stand, but didn't find much. So, now you know... buyer beware!
So, I found a used Salamander Chameleon Sonoma 326. It matches the other furniture perfectly, looks great in the room, and has a perfect amount of storage. And, room on top for the turntable, as well as the Primaluna HP. Makes it look like simple and elegant system. The Salamander is very heavy, and made from solid wood.
But, when I hooked it up, that damn Salamander rings like a bell, and that energy totally transfers to the tonearm. I could not believe how horrible the system now sounded! Clearly the furniture was the problem. It was immediate, and completely ruined the sound. I think part of the issue is that it has a metal frame beneath the wood, and the sides seem to cause the metal frame to vibrate and ring.
Now, I'm on an adventure to see if I can fix it. My plan is 2 inch thick maple platform with vibrapods under the platform. A platform for the amp, a separate one for the TT, and vibrapods under the phono preamp. I have used an old tabletop from Ikea (it's honeycomb inside, and good dampener) with rubber feet, and it's helped a lot. But, I can still tell this vibrates slightly. I don't think it transfers much to the tonearm, but I'm still getting the maple platform.
I'm posting this because I've done some research oil Salamander as a TT stand, but didn't find much. So, now you know... buyer beware!